1. Field of the Invention
The invention relates to a method of curving a glass sheet which has been heated to bending temperature. The method employs a hot gas stream with a large cross sectional area, whereby the glass sheet is pressed against a curving form.
2. Background of the Prior Art
A curving method of this type is described in Ger. OS 35 23 675. In this method, the glass sheet heated to bending temperature is conveyed in a horizontal attitude on a roller conveyor, to a curving station at which it is lifted from the conveyor by means of an upwardly directed hot gas stream with a large cross sectional area and is pressed against a curving form disposed above the conveying rollers, which curving form is convex in the direction toward the conveyor. The glass sheet acquires the shape of the curving form, and is then deposited on a support rng which is operated below the curving form, whereby the glass sheet is transported out of the curving station.
If glass sheets are to be curved, with the aid of this known method, into a shape having, e.g., edge region locations which are deeply curved, the pressure exerted on the edge regions by the gas stream is insufficient under the given conditions to press the glass sheet tightly against the curving form at the locations of these deeply or sharply curved edge regions. As a result, the shape of the curved glass sheet will differ from the prescribed contour of the curving form. it has been found that this difficulty cannot be alleviated by increasing the pressure of the hot gas stream, i.e. by increasing its flow speed.